Description: This function writes a stress file based on d3plot or elout file.
Usage:
1. DSI prompts
• D3PLOT: DSI will prompt to read in a d3plot file
• ELOUT: DSI will prompt to read in a DYNA and a ELOUT file
2. DSI prompts
> ENTER MINIMUM VON STRESS LEVEL
3. Enter a number and file name, then the FDYNAM is written.